Papermaking machine



April 1966 J. J. ASHEN BRUCKER 3,245,153

PAPERMAKING MACHINE Filed April 8, 1963 2 Sheets-Sheet 1 April 12, 1966 J. J. ASHENBRUCKER 3,245,153

PAPERMAKING MACHINE Filed April 8, 1965 2 Sheets-Sheet 2 United States Patent 3,245,153 PAPERMAKENG MACHINE John J. Ashenbrucker, Menasha, Wis., assignor to Kimberly-Clarlr Corporation, Neenah, Wis., a corporation of Delaware Filed Apr. 8, 1963, Ser. N 271,399 2 Claims. (481. 34116) My invention relates to papermaking or paper con verting machines and more particularly to the drier sections of papermaking machines.

In a papermaking machine, the web which is formed by felting together paper fibers from an equeous suspension of such fibers is progressively dried by passing the web over a succession of heated rolls. Although the surface of such a heated roll is very smooth, some individual fibers cling to the roll and must be promptly removed, or lumps will eventually be built up which will indent the paper sheet passing over the roll. This is particularly true with the modern high speed papermaking machines and the practice of coating the paper web with china clay, titanium dioxide and other fillers While the paper is being made on the machine to increase the paper opacity. Fuzz and dust particles on the heated rolls thus create aproblem; and to keep the surface of a roll clean, a doctor glade is customarily employed which is held against the surface and scrapes it clear of any clinging fibers. The problem is aggravated by the electrical action of the rapidity moving web in passing over the drying rolls which generates considerable static electricity on the rolls and on the paper web, so that the dust scraped from each roll by its doctor blade tends to move onto the web, contaminating the web in this respect.

Devices have been previously proposed for collecting the dust and fuzz scraped by each of the doctor blades from its drier roll, and these have involved some type of hood or pocket suspended close to the doctor blade for the purpose of containing the fuzz. Attachments are commonly provided in connection with the pockets for removing the fuzz from the pockets by blowing compressed air through the pockets or by means of a vacuum source connected to the pockets. Such arrangements for removing the fuzz from the pockets require considerable power, particularly for the type utilizing the vacuum source which must be effective for the full width of the web.

It is an object of the present invention to provide a simple, economically operated, and effective mechanism for removing the fuzz or dust from a paper web and from a device operative on or in connection with a paper web, such as a doctor blade effective on a drier roll in a papermaking machine. More particularly, it is an object of the invention to utilize the electrically charged environment generated by the rapid movement of a paper web particularly over the rotating drier rolls of a papermaking machine for drawing 0d the fuzz and dust from the paper web and particularly from a doctor blade effective on such a roll.

In brief, the invention contemplates the provision of a slowly moving belt adjacent the rapidly moving web and particularly adjacent such a doctor blade, with the belt being formed of an electrically non-conducting material that collects charges of static electricity in the charged environment of the web and doctor blade, so that the belt collects and holds the fuzz or dust scraped by the doctor blade from its roll which would otherwise tend to'adhere to and collect on the paper Web. The fuzz or dust may be removed by any suitable mechanism from the belt.

The inventionconsists of the novel constructions, arrangements and devices to be hereinafter described and claimed for carrying out the above stated objects, and

such other objects, as will be apparent from the following description of a preferred form of the invention, illustrated with reference to the accompanying drawings, wherein:

FIG. 1 is a fragmentary, schematic, side elevational view of the drier section of a papermaking machine including a fuzz removing mechanism incorporating the principles of the invention;

FIG. 2 is a fragmentary side elevational view of the drier section on an enlarged scale showing the fuzz removing mechanism of the invention;

FIG. 3 is a fragmentary plan view of the fuzz removing mechanism; and

FIG. 4 is an end view of the fuzz removing mechanism.

Like characters of reference designate like parts in the several views.

The papermaking machine drier section illustrated in FIG. 1 includes rotatable top drying rolls 8 and 9 and a rotatable bottom drying roll 10. A paper web 11 passes over the uppermost portions of the top drying rolls 8 and 9 and around the lowermost peripheral portion of the lowermost drying roll 10. A canvas 12 extends over the uppermost peripheral portions of the rolls 8 and 9 for holding the paper web tightly in contact with the rolls 8 and 9, and the canvas also passes over a canvas guide roll 13. The rolls 8, 9, and it) are heated as by a conventional steam supply and rotate to have the high linear speeds of modern papermaking machines, such as 500 to 3000 feet per minute, for example.

A doctor blade 14 supported by a bracket 15 fixed with respect to the framework of the papermaking machine is provided on the top surface of the roll 10 for the purpose of doctoring off the fuzz and dust particles that are carried by the roll 10 on its periphery and indirectly the fuzz and dust particles carried by the paper web 11.

A dust collecting device 16 is provided adjacent the doctor blade 14 for the purpose of drawing off the dust from the blade 14. The collecting device 16 comprises an endless belt 17 disposed in the form of a loop over a pair of spaced rolls 18 and 19 which are respectively on opposite sides of the machine and are spaced from opposite ends of the drum 10. The roll 19 is rotatably disposed with respect to a bracket 20, which is fixed with respect to a frame part 21 by means of a pair of bolts 22. The bracket 20 is provided with a plurality of spaced holes 23 through it for receiving the bolts 22, allowing the bracket to be adjustably moved to move the roll 19 toward and away from the frame part 21 for taking up slack in the belt 17. The roll 18 is disposed on the end of the output shaft 24 of a speed reducer 25, and the speed reducer 25 is mounted on a bracket 26 which is in turn mouned on an arm 27 swingably disposed about a fixed pivot 28. A motor 29, such as an air motor of any suitable construction, is fixed to the speed reduction unit 25 for driving the unit 25,

An air cylinder 30 is provided for selectively moving the reducer 25, the motor 29, and the belt 17 upwardly. The cylinder 30 comprises a piston 31 connected by means of a piston rod 32 with a bar 33 that is fixed with respect to the framework of the papermaking machine and is thus stationary. The cylinder is fixed with respect to the arm 27 by means of a mounting bar 34, a pivotal connection 35 being provided between the bar 34 and the cylinder 30. A similar cylinder 30 and connections (not shown) may be provided for moving the part 21 upwardly.

A brush 36 is mounted on the bracket 26 for brushing off fuzz and dust collected by the belt 17, and a suction tube 37 is provided for sucking off the fuzz and dust dislodged by the brush 36 from the belt 17.

The belt 17 may be made of many different materials but preferably should be of an electrical insulating material that is capable of collecting and building up electrostatic charges on its surface. The belt, for example, may be made of an outer strip of homogeneous nylon backed by an inside strip of woven nylon cloth that runs over and is in contact with the rollers 18 and 19. As is well known, nylon is organic and synthetic and is a polyamide. Other organic synthetic materials, such as dacron, which is a polyester, and orlon, which is an acrylic, might also be used, for example; and I also consider some inorganic materials capable of collecting electrostatic charges, such as glass fiber, for example, to be suitable. In order to assist static charges in remaining on the belt 17, the rollers 18 and 19 are preferably of insulating materials. The belt may be quite thin, such as inch to inch thickness, and may, for example, be 1 to 2 inches wide. The belt is preferably driven by the motor 29 and speed reduction unit 25 at a speed which is slow compared to the speed of the web 11, such as, for example, at a belt speed of about 30 feet per minute. The belt 17 is located adjacent to the doctor blade 14, such as about an inch away from the tip of the blade 14, for example.

In operation, the paper web 11 accumulates a static charge in moving over the drying rolls 8, 9, and 19 and the other drying rolls of the papermaking machine drier section, and the belt 17 is thus disposed in a statically charged environment. The belt accumulates an electrostatic charge on it not only due to the fact that it is disposed in this statically charged environment but also due to the fact that the belt is driven by means of the motor 29 and speed reducer 25 over its supporting rolls 18 and 19. The paper fuzz or dust scraped by the blade 14 from the roll is thus drawn off and accumulated on the belt 17 and travels with the belt to the brush 36. The brush 36 removes the dust and fuzz from the surface of the belt 17, and the suction pipe 37 keeps the brush 36 clean of this fuzz.

In the event that it is desired to have working access to the doctor blade 14 during cleaning of the papermaking machine, one end of the belt 17 may be raised by supplying air under pressure to the illustrated cylinder 30. The air pressure on the cylinder 30 moves it upwardly with respect to the piston 31 connected to thestationary part 33 and thus swings the arm 27 and the connected parts upwardly. Air pressure supplied to a similar cylinder 30 (not shown) connected to the part 21 simultaneously raises the other end of the belt 17.

Dust collecting devices 16A and 16B similar to the device 16 may be provided for the upper rolls 8 and 9, and similar dust collecting devices may be provided for each of the other heated rolls in the drier section of the papermaking machine.

Although the dust collecting device v16 comprising the electrostatic charge collecting belt 17 has been described and illustrated in connection with the doctor blade 14, such dust collecting belts according to the invention may also be used in connection with printing presses or other types of paper working machinery, such as, for example, paper cutters or slitters. In these cases, the dust collecting belt is placed close to the paper web or may even carry the paper web. The paper fuzz collected by the belt may be removed from the belt similarly as has been above described, such as by means of a brush 36.

The dust collecting devices of the invention efficiently and thoroughly remove paper dust and fuzz from the paper web, drying rolls for the web, and doctor blades effective on the rolls. The dust collecting devices advantageously require little power for operating them and are relatively simple in construction. The charge collecting belt 17 of the collecting device 16 is particularly effective in collecting dust and fuzz from the paper web, since the belt 17 along with the adjacent doctor blade 14 is disposed between nearly vertical passes of the web 11 from the roll 1%) in the lowermost bank of rolls to the rolls 8 and 9 in the uppermost bank of rolls. The paper web 11, as will be observed from FIG. 1, is in contact with some what more than of the periphery of each of the drier rolls so as to produce these nearly vertical passes of the web 11 between which the belt 17 is disposed. The web 11 accumulates an electrostatic charge in rapidly passing over the rotating drier rolls including the rolls 8, 9 and 10; and, since the belt .17 is in close proximity to and is surrounded on both sides by the web 11, it also, without any other source of electricity, accumulates a strong electrostatic charge for performing its dust and fuzz collecting function.

I wish it to be understood that the invention is not to be limited to the specific constructions, ararngements anddevices shown and described, except only insofar as the claims may be so limited, as it will be understood to those skilled in the art that changes may be made without departing from the principles of the invention.

What is claimed is:

1.. In the drier section of a papermaking machine, a plurality of rotatable heated drier rolls disposed in upper and lower banks so that paper web may pass alternately over the rolls in the two banks with the web contacting each roll for about 180 of its circumference to have nearly vertical passes between the upper and lower banks, a doctor blade for doctoring off paper fuzz from one of the rolls and disposed between the vertical passes of web extending to said one roll, an endless belt, means including a pair of rolls for supporting said belt so that it extends along and adjacent said doctor blade and between the passes of web extending ot said one roll, means for driving one of said pair of rolls so that said belt travels at a speed which is relatively slow with respect to the speed of said heated rolls, the web moving over said heated rolls accumulating an electric charge and said endless belt being made of an electric insulating material whereby an electric charge transfers from the web to the belt so that the belt collects the fuzz from the doctor blade due to the electrostatic charge on the belt, and means for removing and collecting the paper fuzz from said belt.

2. In a machine constructed for performing a manufacturing operation on paper, a plurality of rotatable rolls for conveying a paper web from one roll to another, said rolls being so disposed that at least one of said rolls has the paper web passing around it for about 180 of its circumference to have ingoing and outgoing passes of the paper web extending generally parallel to each other, a doctor blade in contact with the portion of said one roll not covered by the web for doctoring off paper fuzz from the roll, an endless belt, means including a pair of belt supporting rolls for supporting said belt so that it extends along and adjacent said doctor blade and between the passes of web extending to said one roll, and means for driving one of said belt supporting rolls so that said belt travels at a speed which is relatively slow with respect to the speed of said first named rolls, the paper web passing over said first named rolls accumulating an electric charge and said endless belt being made of an electric insulating material whereby an electric charge transfers from the paper web to the belt so that the belt collects the fuzz from the doctor blade due to the electrostatic charge on the belt.

References Cited by the Examiner UNITED STATES PATENTS 296,148 4/1884 Delmage 15 1.5 2,586,014 2/1952 Dunphy 3485 2,832,977 5/1958 Walkup et a1 15 1.5 2,859,537 11/1958 Shockey "34-85 WILLIAM F. ODEA, Primary Examiner. NORMAN YUDKOFF, Examiner. 

1. IN THE DRIER SECTION OF A PAPERMAKING MACHINE, A PLURALITY OF ROTATABLE HEATED DRIER ROLLS DISPOSED IN UPPER AND LOWER BANKS SO THAT PAPER WEB MAY PASS ALTERNATELY OVER THE ROLLS IN THE TWO BANKS WITH THE WEB CONTACTING EACH ROLL FOR ABOUT 180* OF ITS CIRCUMFERENCE TO HAVE NEARLY VERTICAL PASSES BETWEEN THE UPPER AND LOWER BANKS, A DOCTOR BLADE FOR DOCTORING OFF PAPER FUZZ FROM ONE OF THE ROLLS AND DISPOSED BETWEEN THE VERTICAL PASSES OF WEB EXTENDING TO SAID ONE ROLL, AN ENDLESS BELT, MEANS INCLUDING A PAIR OF ROLLS FOR SUPPORTING SAID BELT SO THAT IT EXTENDS ALONG AND ADJACENT SAID DOCTOR BLADE AND BETWEEN THE PASSES OF WEB EXTENDING TO SAID ONE ROLL, MEANS FOR DRIVING ONE OF SAID PAIR OF ROLLS SO THAT SAID BELT TRAVELS AT A SPEED WHICH IS RELATIVELY SLOW WITH RESPECT TO THE SPEED OF SAID HEATED ROLLS, THE WEB MOVING OVER SAID HEATED ROLLS ACCUMULATING AN ELECTRIC CHARGE AND SAID ENDLESS BELT BEING MADE OF AN ELECTRIC INSULATING MATERIAL WHEREBY AN ELECTRIC CHARGE TRANSFERS FROM THE WEB TO THE BELT SO THAT THE BELT COLLECTS THE FUZZ FROM THE DOCTOR BLADE DUE TO THE ELECTROSTATIC CHARGE ON THE BELT, AND MEANS FOR REMOVING AND COLLECTING THE PAPER FUZZ FROM SAID BELT. 